Editor’s note: This is Part 1 of a two-part series by Xu Fanglei examining the technology and patent issues behind the Stratasys-Bambu Lab dispute.Part 1 looks at the U.S.verdict and the technology at the center of the case.
Part 2 will examine the related proceedings in Europe and the broader patent fight.Over the past few days, one story has circulated repeatedly across the 3D printing community: the patent lawsuit between Stratasys and Bambu Lab reached a verdict in the U.S.District Court for the Eastern District of Texas.
On September 18, 2026, a federal jury in the Eastern District of Texas found that companies associated with Bambu Lab infringed four Stratasys patents.The jury awarded approximately $27.6 million in damages, equivalent to roughly RMB 185 million.But the dollar amount only tells part of the story.
Behind the verdict is a much more technical fight over how modern desktop 3D printers work, including technology that many users probably rarely think about.Over the past few days, I reviewed publicly available court records, patent documents, and developments in related proceedings.I’m not a lawyer.
I’m a designer who has worked in industrial design and 3D printing for years, so I wanted to look at the case from a product and technology perspective.What is this patent battle actually about? And there’s another question I find even more interesting: Why can essentially the same technology lead to different outcomes in the United States and Europe? A Patent Fight Two Years in the Making This story has actually been going on for more than two years.On August 8, 2024, Stratasys filed two patent infringement lawsuits against Bambu Lab and related companies in the U.S.
District Court for the Eastern District of Texas.The two cases originally involved ten patents.The court later consolidated the cases for pretrial purposes, while the litigation continued across multiple procedural tracks.
The main case discussed here is: Stratasys, Inc.v.Shenzhen Tuozhu Technology Co.
Ltd.et al., Case No.2:24-cv-00644.
But if you want to dig into the details yourself, the CourtListener docket is probably the easiest place to start.From the public record, this was never simply a case of “one company sued another over one product.” In fact, the dispute involved multiple patents, questions of infringement and patent validity, and proceedings in different courts and before the USPTO.In other words, the case is considerably more complicated than the headline suggests.
Stratasys initially asserted patents covering several areas of 3D printing technology, including printing methods, purge towers, force detection, and networked printing.For the September 2026 jury trial, four patents were ultimately at issue: U.S.Patent Nos.
9,421,713, 7,555,357, 9,168,698, and 10,556,381.The damages were roughly $14.2 million for technology involving purge towers in multi-material or multi-color printing, $10.6 million for an extrusion-based 3D printing method, and $2.8 million combined for two force-detection patents.So the $27.6 million figure is not a blanket finding that “Bambu Lab infringed all of Stratasys’ patents.” Rather, the damages are tied to specific patents, technologies, and sales periods.
The Little Tower Next to the Print For me, the most interesting part isn’t the $27.6 million.Yes, it’s a huge number.But as someone who works in product design and technology, I find it more interesting to look at what these patents are actually protecting.
And one patent in particular caught my attention: U.S.Patent No.9,421,713.
Stratasys’ Fortus 450mc industrial FDM 3D printer.Stratasys is pursuing patent infringement claims against Bambu Lab involving several 3D printing technologies.Image courtesy of Stratasys.
This patent involves something almost everyone who has used a multi-color 3D printer has seen: the purge tower, sometimes called a prime tower.A single-nozzle, multi-material 3D printer has to deal with a simple problem.When the printer switches from one filament or color to another, some of the previous material remains inside the nozzle and melt zone.
If the printer starts printing with the new material immediately, the two materials can mix.So the printer first needs to push out some of the old material.And that’s where the little tower next to your model comes from.
It looks incredibly simple.But that’s exactly where things get interesting: At what point does a purge-tower implementation become covered by a patent? Simply having a purge tower does not automatically mean infringement.Bambu Lab has purge towers.
Stratasys’ patent also describes purge-tower technology.And many other printers use some form of purge structure.The important question is not simply whether the tower exists.
The question is whether the accused implementation contains the specific technical features required by the patent claims.And this is where one particular phrase becomes important: “layer by layer.” Bambu Lab’s X1 Carbon is among the 3D printers at the center of Stratasys’ patent infringement case against the company.Image courtesy of Bambu Lab.
Three Words: “Layer by Layer” Indeed, one interesting issue in this patent is the phrase “layer by layer manner.” To me, those words don’t sound particularly dramatic.But when you pair the patent language with the actual printing process, you can see why the interpretation matters.Let me put it more simply.
Imagine the purge tower as a small rectangular column made up of many layers: Layer 1.Layer 2.Layer 3.
And so on.Now ask a seemingly simple question: What exactly is allowed to happen within each layer? That is where things get technically interesting.The dispute turns in part on how the patent’s claimed method should be understood, particularly how it deposits material to form the purge structure.
Bambu Lab’s position has focused on differences in how its printers generate that structure, including the fact that different material paths can appear within the same horizontal printing layer.That creates a subtle but important technical distinction.From the outside, two printers may appear to be doing the same thing: Change color → purge the nozzle → print the purge tower → continue printing the model To the user, there may be almost no visible difference.
But once you break the process down to the engineering level, things become much more complicated: How is the material extruded? When does the material switch? When is the purge tower printed? How is each layer formed? How are model material and support material handled? Those details can become the heart of a patent dispute.The court’s pretrial proceedings also addressed questions about the scope of the asserted patent claims and how they apply to single-nozzle 3D printing systems.That’s exactly why I find this case interesting as a designer.
It reminds me of industrial design.When we look at a product, we first see the exterior.But what actually determines how the product works is often hidden inside: how a mechanism moves, how two components interact, how material flows, when a sensor activates, or when an algorithm steps in.
Many valuable technology patents ultimately protect these invisible details.If the patent language above feels a little abstract, the diagram below should make the difference much easier to understand.Left: Purge tower formed with a single material.
Right: Purge tower containing multiple materials.Image courtesy of Bambu Lab.The real dispute isn’t simply “whether there are two materials.” The more important question is whether different materials appear within the same horizontal layer during printing, and whether that falls within the technical scope defined by the patent claims.
In Part 2, Xu looks at how this same technical issue played out in Europe, why the Unified Patent Court reached a different conclusion in its preliminary proceedings, and where the broader Stratasys-Bambu Lab patent dispute goes from here.Subscribe to Our Email Newsletter Stay up-to-date on all the latest news from the 3D printing industry and receive information and offers from third party vendors.Print Services Upload your 3D Models and get them printed quickly and efficiently.
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